When two men grab their own dicks and pull them back opposite of each other and release at the same time. This releasing a shockwave.

The act of getting a blowjob by two girls while eating a sandwich and taking a dump.

A large biscuit so large it may be 4 times bigger than above average

Possibly the worst invention in history. The double decker outhouse is, quite literally, two toilet stalls stacked. Although this structure conserves space, it is completely impractical and downright messy.

The action of twerking while on top of someone else who is also twerking. Created by Ian and Anthony of Smosh during their seven hour live-cast for their Food Battle The Video Game fundraiser

A sexual position (FFM) where two women are stacked atop one another both doggy-style and faced in the same direction, so all the male sees from behind is two pussies atop each other, hence the "double decker" pussy.

the result of massive insertion of smokeless tobacco in the lower and upper jaw at the same time, resulting in a twin horseshoe shape of tobacco. When performed with loosleaf tobacco, it is known as the chokey chubby chew.